Toxicities of p-nitrotoluenes and their effects on blood corpuscles and ovaries in Crusian carps （ Carassius auratus ）

1 Introduction p-nitrotoluene is an important organic intermediate widely used to produce pesticides, foamed plastics, dyestuffs and medicines. It is also a significant N-nutrient source in water (Zhu Jun et al., 2005). One will display such disorders a…     

Kinetic Spectrophotometric Determination of Trace Iron（Ⅲ）with p—Amino—N,N—Dimethylaniline Dihydrochloride and Hydrogen Peroxide

A new, simple and highly sensitive kinetic method for the determination of trace iron (III) has been developed based on the catalytic effect of iron (III) on color reaction ofp-amino-N, N-dimethylaniline dihydrochloride (p-DMA) oxidated by hydrogen peroxide. The reaction is followed spectrophotometrically by measuring the absorbance at 510 nm. The detection limit is 4.47×10⁻¹¹ g/ml, and the calibration curve is linear in the range of 0–0.10μg Fe(III) /25 ml with a relative standard deviation of ±3.25%. The method has been applied to the determination of iron in tap-water, chemical reagents and human hair.     

Limitation and combined effects of iron and phosphorus on the growth of <Emphasis Type="Italic">Prorocentrum micans</Emphasis> Ehrenberg (Dinophyceae) and <Emphasis Type="Italic">Cryptomonas</Emphasis> sp. (Cryptophyceae)

Iron and phosphorus limitation and their combined effects on the growth and development of Prorocentrum micans Ehrenberg (Dinophyceae) and Cryptomonas sp. (Cryptophyceae) have been studied. The growth status of these algae at different Fe and P levels is quantitatively analyzed through lab-culture experiments. Results show that Fe starvation can misalign chloroplast lamellas, and metamorphose and twist thylakoid, leading to a retarded growth rate. The combined effects of Fe and P can accelerate their growth, and an optimum culture condition to maintain the maximum growth rate is a combination of 0.05 μM Fe and 50 μM P. Algal uptake of Fe and P are synergistic. Their cellular concentrations bear significant correlations (r = 0.9979 for Cryptomonas sp. and 0.9938 for P. micans; P < 0.01) and correspondingly the molar P:Fe ratios are ∼160:1 and ∼356:1, respectively. These findings will provide novel insights for revealing the crucial factors controlling the occurrence of algal blooms.     

Compositions and sources of extractable organic matter in Mesopotamian marshland surface sediments of Iraq. I: aliphatic lipids

Shallow surface sediment samples from the Mesopotamian marshlands of Iraq were collected and analyzed to determine the distribution, concentrations and sources of aliphatic lipid compounds (n-alkanes, n-alkanols, n-alkanoic acids, and methyl n-alkanoates) and molecular markers of petroleum in these wetlands. The sediments were collected using a stainless steel sediment corer, dried, extracted with a dichloromethane/methanol mixture and then analyzed by gas chromatography-mass spectrometry (GC–MS). The aliphatic lipid compounds included n-alkanes, n-alkanoic acids, n-alkanols and methyl n-alkanoates with concentrations ranged from 6.8 to 31.1 μg/g, 4.1 to 5.0 μg/g, 5.9 to 7.7 μg/g and from 0.3 to 5.9 μg/g, respectively. The major sources of aliphatic lipids were natural from waxes of higher plants (24–30%) and microbial residues (42–30%), with a significant contribution from anthropogenic sources (27–30%, petroleum), based on the organic geochemical parameters and indices. Further studies are needed to characterize the rate, accumulation and transformation of various organic matter sources before and after re-flooding of these wetlands.     

Partition of arsenic in soils sediments and the origin of naturally elevated concentrations in groundwater of the southern pampa region (Argentina)

Excessive arsenic concentrations above the Argentinean and WHO guidelines for drinking water (10 μg L⁻¹) affects shallow aquifers of the southern Pampean Plain (Argentina) hosted in the Pampean and the Post Pampean formations (loess and reworked loess; Plio-Pleistocene–Holocene). Health problems related to high As concentrations in drinking waters are known as Endemic Regional Chronic Hydroarsenicism. Hydrochemistry of shallow groundwaters and soil geochemistry were investigated aiming to (1) understand the partition of As in the solid phase and its relationship with unacceptable As concentrations in waters, (2) identify the provision source of As to groundwaters. Only 5% of the samples had As concentrations <10 μg L⁻¹; in 27% As concentrations ranged from 10 to 50 μg L⁻¹ and in 58% it reached 60–500 μg L⁻¹. The coarse fraction (50–2,000 μm) hosts about 27% of the total As in the solid phase, being positively correlated to Ba (p < 0.01; r ² = 0.93). About 70% is included in the <2 μm fraction and had positive correlations of As–Fe (p < 0.05; r ² = 0.85) and As–Cr (p < 0.05; r ² = 0.68). Soils and sediment sand fractions of vadose zones are the primary sources of As in shallow groundwater while adsorption–desorption processes, codisolution–coprecipitation, and evaporation during the dry seasons raise As concentrations in waters exceeding the guideline value for drinking water.     

Variations of foliar carbon isotope discrimination and nutrient concentrations in Artemisia ordosica and Caragana korshinskii at the southeastern margin of China’s Tengger Desert

Seasonal variations in foliar stable carbon isotope discrimination (Δ) of Artemisia ordosica and Caragana korshinskii and correlations of foliar Δ with N, P, and K concentrations were studied under different planting regimes at the southeastern margin of China’s Tengger Desert. Foliar Δ, N, P, and K concentrations and the correlations of Δ with N, P, and K differed between the species and planting regimes. Foliar Δ, P and K concentrations in A. ordosica were markedly higher than in C. korshinskii, while foliar N concentrations in C. korshinskii was significantly higher than in A. ordosica. There were no significant differences in N, P, and K concentrations in C. korshinskii between planting regimes, but foliar Δ was significantly increased after June in mixed-species planting. In A. ordosica foliar N concentrations in mixed-species planting and foliar Δ in single-species planting were significantly higher than those of corresponding planting regimes. According to water-use efficiency (WUE) calculated based on foliar Δ, and on N, P, and K concentrations, C. korshinskii’s survival may profit from its higher WUE, whereas A. ordosica can avoid drought damage by its higher P and K concentrations in leaves in arid or semi-arid environments. The complex correlations of foliar Δ with foliar N, P and K suggested that water in C. korshinskii and water and P nutrition in A. ordosica were the key factors limiting their growth.     

Distribution of particulate organic carbon in the central Bay of Bengal

Particulate organic carbon (POC) was measured for 77 water samples collected over a 3000 m water column along 88° E in the central Bay of Bengal. The POC values varied from 80 to 895 μg per litre at the surface and 171 to 261 μg per litre at 2000 m. The POC decreased with increasing water depth at all the stations. Deep water concentrations of POC were higher than those reported from other oceanic waters. Distribution of POC was not influenced by water masses. The POC was not significantly correlated with chlorophylla.     

Compositions and sources of extractable organic matter in Mesopotamian marshland surface sediments of Iraq: II. Polar compounds

The concentrations of polar organic compounds including n-alkanoic acids, n-alkanols, steroids and triterpenoids were determined in extracts of shallow sediments from the Mesopotamian marshlands of Iraq. The sediments were collected by a stainless steel sediment corer, extracted with a dichloromethane and methanol mixture (3:1 v:v) by ultrasonic agitation and then analyzed by gas chromatography–mass spectrometric (GC–MS). The analysis results showed that the n-alkanoic acids ranged from C₈ to C₂₀ with concentrations of 7.8 ± 1.2 μg/g sample, whereas the concentrations of n-alkanols, which ranged from C₁₂ to C₃₉ were from 28.6 ± 4.3 to 121.7 ± 18.3 μg/g sample. The steroids and triterpenoids included stenols, stanols, stenones, stanones, tetrahymanol, tetrahymanone and extended ββ-hopanes. The total concentrations of steroids and triterpenoids ranged from 26.8 ± 4.1 to 174.6 ± 26.2 μg/g and from 0.74 ± 0.11 to 11.2 ± 1.7 μg/g sample, respectively. The major sources of these lipids were from natural vegetation, microbial (plankton) residues and bacteria in the sediments, with some contribution from anthropogenic sources (livestock, sewage and petroleum). Further studies of these wetlands are needed to characterize the input rate, transformation and diagenesis of the organic matter and to assess its various sources.     

Effects of light intensity on the growth of <Emphasis Type="Italic">Cryptomonas</Emphasis> sp. (Cryptophyceae)

Laboratory culture experiments have been conducted to evaluate the effects of light intensity on the growth of Cryptomonas sp. (Cryptophyceae) and the discrepancy in absorption of iron and phosphorus under different light conditions. Results show that there is an exponential correlation between algal growth rate and light intensity. The saturating and semi-saturating light values for Cryptomonas sp. cells are 150 and 47 μmol photons m⁻² s⁻¹, respectively. More uptake of Fe, P, and other trace elements such as Zn, Mn, Co, and Mo is observed in the low light cultures, although the algal growth rates are slow. The growth rate at 10 μmol photons m⁻² s⁻¹ is only 10% of that at 150 μmol photons m⁻² s⁻¹, whereas Fe and P uptake increases by 150 and 100%, respectively. These results suggest potential implications of differentiation in absorption of iron and phosphorus at different light intensities for the occurrence of harmful algal blooms (HABs). The mechanisms of light intensity regulating nutrient uptake as well as the occurrence of HABs are also discussed.     

Exposure and bioavailability of arsenic in contaminated soils from the La Parrilla mine, Spain

Arsenic derived from mining activity may contaminate water, soil and plant ecosystems resulting in human health and ecotoxicological risks. In this study, exposure assessment of arsenic (As) in soil, spoil, pondwater and plants collected from the areas contaminated by mine tailings and spoils in and around the La Parrilla mine, Caceres province, Spain, was carried out using AAS method. Water solubility, bioavailability and soil–plant transfer coefficients of As and phytoremediation potential of plants were determined. Arsenic concentrations varied from 148 to 2,540 mg/kg in soils of site 1 and from 610 to 1,285 mg/kg in site 2 exceeding the guideline limit for agricultural soil (50 mg/kg). Arsenic concentrations in pond waters varied from 8.8 to 101.4 μg/l. High concentrations of water-soluble As in the soils that ranged from 0.10 to 4.71 mg/kg in site 1 and from 0.46 to 4.75 mg/kg in site 2 exceeded the maximum permitted level of water-soluble As (0.04 mg/kg) in agricultural soils. Arsenic concentrations varied from 0.8 to 149.5 mg/kg dry wt in the plants of site 1 and from 2.0 to 10.0 mg/kg in the plants of site 2. Arsenic concentrations in plants increased in the approximate order: Retama sphaerocarpa < Pteridium aquilinum < Erica australis < Juncus effusus < Phalaris caerulescens < Spergula arvensis in site 1. The soil–plant transfer coefficients for As ranged from 0.001 to 0.21 in site 1 and from 0.004 to 0.016 in site 2. The bioconcentration factor based on water-soluble As of soil varied from 3.2 to 593.9 in the plants of site 1 whereas it varied from 2.1 to 20.7 in the plants of site 2. To our knowledge, this is the first study in Europe to report that the fern species P. aquilinum accumulates extremely low contents of As in its fronds despite high As levels in the soils. Therefore, the S. arvensis, P. caerulescens and J. effusus plant species grown in this area might be used to partly remove the bioavailable toxic As for the purpose of minimization of mining impacts until hypothetical hyperaccumulating and/or transgenic plants could be transplanted for the phytoremediation of As contaminated soils.     

Omphacite breakdown reactions and relation to eclogite exhumation rates

Clinopyroxene + plagioclase (±Hbl ± Qtz) symplectites after omphacite are widely cited as evidence for prior eclogite-facies or high-pressure (HP) metamorphism. Precursor omphacite compositions of retrograde eclogites, used for reconstructing retrograde P–T paths, are commonly estimated by reintegrating symplectite phases with the assumption that the symplectite-forming reactions were isochemical. Comparisons of broadbeam symplectite compositions to adjacent unreacted pyroxene from various symplectites after clinopyroxene from the Appalachian Blue Ridge (ABR) and Western Gneiss Region (WGR) suggest that the symplectite forming reactions are largely isochemical. Endmember calculations based on reintegrated symplectite compositions from the ABR and WGR suggest that a minor Ca-Eskola (CaEs) component (X_CaEs = 0.04–0.15) was present in precursor HP clinopyroxene. WGR symplectites consist of fine-grained (∼1 μm-scale), vermicular intergrowths of Pl + Cpx II ± Hbl that occur at grain boundaries or internally. ABR symplectites contain coarser (∼10 μm-scale) planar lamellae and rods of Pl + Cpx II + Qtz + Hbl within clinopyroxene cores. The contrasting textures correlate with decompression and cooling rate, and degree of overstepping of the retrograde reaction (lamellar: slow, erosionally controlled exhumation with slow/low overstepping; fine-grained, grainboundary symplectite: rapid, tectonic exhumation with rapid/high overstepping). Variations in X_CaEs, X_jd, and X_CaTs of precursor HP omphacite are related to the symplectic mineral assemblages that result from decompression. Quartz-normative symplectities indicate quartz-producing retrograde reactions (e.g., breakdown of precursor CaEs); quartz-free symplectities (e.g., diopside + plagioclase after omphacite) indicate quartz-consuming reactions (jd, CaTs breakdown) outpaced quartz-producing reactions. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Vulnerability of groundwater in Quaternary aquifers to organic contaminants: a case study in Wuhan City,China

More than 30 organic contaminants were detected in shallow groundwaters at Wuhan, the largest city in central China. Seriously contaminated groundwaters were from densely populated, industrial and commercial areas. Abnormal concentrations were found in groundwater from Hankou, downtown Wuhan: trimethylbenzene up to 29 μg/L, tetramethylbenzene up to 866 μg/L, and trichloroethene up to 9.5 μg/L. Benzene, Toluene, Ethylene and Xylene (BTEX) contamination of groundwater is serious and widespread at Wuhan, ranging between 0.14 and 25.0 μg/L. Considering the hydrogeological conditions of most Chinese cities, DRAMIC, a modified version of the widely used DRASTIC model, was proposed by the authors for assessing vulnerability of groundwater to contamination. The factors D, R, A and I in DRAMIC model are the same as in DRASTIC. The factor topography is ignored. The factor soil media is substituted by a new factor aquifer thickness (M) and the factor hydraulic conductivity of the aquifer by a new factor impact of contaminant (C). The equation for determining the DRAMIC Index is: DRAMIC = 5D _R + 3R _R + 4A _R + 2M _R + 5I _R + 1C _R. The calculated DRAMIC Index can be used to identify areas that are more likely to be susceptible to groundwater contamination relative to each other. The higher the DRAMIC Index is, the greater the groundwater pollution potential. Applying DRAMIC, a GIS-based vulnerability map for Wuhan city was prepared. Interestingly, places such as downtown Hankou, where enhanced concentrations of BTEX have been detected, correspond quite well with those with higher DRAMIC ratings.     

Primary productivity in the German Bight (1994–1996)

Within the KUSTOS program (Coastal Mass and Energy Fluxes-the Land-Sea Transition in the Southeastern North Sea) 28 to 36 German Bight stations were seasonally surveyed (summer 1994, spring 1995, winter 1995–1996) for light conditions, dissolved inorganic nutrient concentrations, chlorophylla (chla), and photosynthesis versus light intensity (P:E) parameters. Combining P:E curve characteristics with irradiance, attenuation, and chlorophyll data resulted in seasonal estimates of the spatial distribution of total primary production. These data were used for an annual estimate of the total primary production in the Bight. In winter 1996 the water throughout the German Bight was well mixed. Dissolved inorganic nutrient concentrations were relatively high (nitrogen [DIN], soluble reactive phosphorus [SRP], and silicate [Si]: 23, 1, and 10 μM, respectively). Chla levels generally were low (< 2 μg l⁻¹) with higher concentrations (4–16 μg l⁻¹) in North Frisian coastal waters. Phytoplankton was limited by light. Total primary production averaged 0.2 g C m⁻² d⁻¹. Two surveys in April and May 1995 captured the buildup of a strong seasonal thermo-cline accompained by the development of a typical spring diatom bloom. High nutrient levels in the mixed layer during the first survey (DIN, SRP, and Si: 46, 0.45, and 11 μM, respectively) decreased towards the second survey (DIN, SRP, and Si: 30.5, 0.12, and 1.5 μM, respectively) and average nutrient ratios shifted further towards highly imbalanced values (DIN:SRP: 136 in survey 1, 580 in survey 2; DIN:Si: 13.5 in survey 1, 96 in survey 2). Chla ranged from 2 to 16 μg l⁻¹ for the first survey and rose to 12–50 μg l⁻¹ in the second survey. Phytoplankton in nearshore areas continued to be light limited during the second survey, while data from the stratified regions in the open German Bight indicates SRP and Si limitation. Total primary production ranged from 4.0 to 6.3 g C m⁻² d⁻¹. During summer 1994 a strong thermal stratification was present in the German Bight proper and shallow coastal areas showed unusually warm (up to 22°C), mixed waters. Chla concentrations ranged from 2 to 18 μg l⁻¹. P:E characteristics were relatively high despite the low nutrient regime (DIN, SRP, and Si: 2, 0.2, and 1.5 μM, respectively), resulting in overall high total primary production values with an average of 7.7 g C m⁻² d⁻¹. Based on the seasonal primary production estimates of the described surveys a budget calculation yielded a total annual production of 430 g C m⁻² yr⁻¹ for the German Bight.     

Below-thunderstorm rain scavenging of urban aerosols in the health hazardous modes

A very high number concentration of aerosols in urban locations has a wide impact on health and ecosystem. The evolutions of urban aerosol distributions at elapse-time 30 and 60 min are simulated at rainfall rates, 0.5 and 0.9 mm h⁻¹ applying scavenging coefficients to initial aerosols number concentrations (before rain). We show how thunderstorm rain scavenges number concentrations of urban aerosols in the ultrafine and fine modes. Elapsed-time evolutions of urban aerosols presented in this work show washout of about 50–60 and 70–80% number concentrations of particles in the diameter range 0.02 μm ≤ D _p  ≤ 0.1 μm after 30 and 60 min of thunderstorm rain when compared to initial number concentrations (before rain). Assuming 37 and 24% Sulfate and Organic Carbon particles in aerosol distributions in the urban environment and by applying scavenging coefficients to these initial number concentrations, elapse-time evolutions after 30 and 60 min of thunderstorm rain are presented in this work. The health impact is addressed in terms of depositions of particles within respiratory system by deposition fractions as a function of particle size. For D _p  ≤ 0.1 μm, 33 and 41% of initial number concentrations of Sulfate and Organic Carbon particles deposits within respiratory system. Whereas elapsed-time evolutions show 60 and 80% cleansing of initial number concentrations of Sulfate and Organic Carbon particles after 30 and 60 min of thunderstorm rain.     

Dissolved Uranium and 234U/238U in the Yamuna and the Chambal Rivers, India

Dissolved uranium concentration and ²³⁴U/²³⁸U activity ratio have been measured in two distinctly different Indian drainage systems: the Yamuna headwaters in the Himalaya and the Chambal river system in the plains to study the weathering and mobility of uranium in these watersheds. The dissolved uranium in the Chambal river system ranges from 0.2 to 1.74 μg L⁻¹ during September (tail end of monsoon), whereas in the Yamuna river system, its concentration varies from 0.1 to 3.18 μg L⁻¹ during October (post-monsoon) and from 0.09 to 3.61 μg L⁻¹ in June (summer). In the Yamuna main stream, uranium is highest at its source and decreases steadily along its course, from 3.18 μg L⁻¹ at Hanuman Chatti to 0.67 μg L⁻¹ at Batamandi, at the base of the Himalaya. This decrease results mainly from mixing of the Yamuna mainstream with its tributaries, which are lower in uranium. The high concentration of uranium at Hanuman Chatti is derived from weathering of the Higher Himalayan Crystalline series (HHC) and associated accessary minerals, which may include uranium-mineralised zones. The ²³⁴U/²³⁸U activity ratios in the samples from the Chambal watershed are in the range of 1.15±0.05 to 1.67±0.04; whereas in the Yamuna the ratios vary from 0.95±0.03 to 1.56±0.07, during post-monsoon and from 0.98±0.01 to 1.30±0.03, during summer. The relatively high ²³⁴U/²³⁸U activity ratios in the Yamuna system are in its tributaries from the lower reaches viz., the Amlawa, Aglar, Bata, Tons and the Giri. It is estimated that ~9×10³ and ~12 × 10³ kg of dissolved uranium are transported annually from the Yamuna at Batamandi and the Chambal at Udi, respectively. This corresponds to uranium weathering rates of 0.9 and 0.09 kg U km⁻² y⁻¹ in the basins of the Yamuna and the Chambal headwaters. This study confirms that uranium weathering rate in the Himalaya is far in excess (by about an order of magnitude) of the global average value of ~0.08 kg U km⁻² y⁻¹.     

Elastic properties and stability of coexisting 3T and 2M 1 phengite polytypes

The elastic properties of coexisting natural 3T and 2M ₁ phengite samples (Cima Pal, Sesia Zone; Val Savenca; Western Alps, Italy) with similar chemical compositions have been studied by room temperature–high pressure powder diffraction, using synchrotron radiation on the ID9A beam-line at ESRF (Grenoble, France). The P–V curves have been modelled by the Birch–Murnaghan model; a third-order expansion fitted to the experimental data yields for 3T and 2M ₁ K ₀=60.4(±0.7) GPa, K′=5.79(±0.11) at V ₀=703.8851 ų, and K ₀=57.3(±1.0) GPa, K′=6.97(±0.24) at V ₀=938.8815 ų, respectively. The relative stability of 3T vs. 2M ₁ has been explored as a function of pressure and temperature in terms of configuration and deformation contributions to the Gibbs energy, using the elastic properties determined here and other thermodynamic parameters from earlier investigations. The results presented agree with the hypothesis of stability of the 3T polytype in the high pressure regime.     

Distribution of arsenic and mercury in subtropical coastal beachrock,Gulf of Mannar,India

An assessment of coastal pollution was made on the basis of trace element concentrations (arsenic — As, mercury — Hg) in the Gulf of Mannar. The beachrock samples were collected along the coastal tracts between Rameswaram and Kanyakumari. The samples were dried and digested to determine the As and Hg using atomic absorption spectrophotometer (AAS-air-acetylene and nitrous oxide method). The As and Hg accumulation status of the beachrock was assessed using geo-accumulation index values (I _geo). The accumulation of As and Hg in the beachrock ranges from 2.75 to 20.72 μg g⁻¹ and from 0.06 to 0.31 μg g⁻¹, respectively. The As and Hg concentrations in the beachrocks are compared with crustal average values and average of other region sediments. The possible source of the contamination is from atmospheric deposition and anthropogenic activities.     

Characterization of insolubilized humic acid and its sorption behaviors

Insolubilized humic acid (IHA) was prepared in the laboratory by heating approach. Through the comparison between the endothermic peaks, optimal heating temperature was determined to be 330°C. The modified IHA then was characterized by TG-DTA, SEM, FTIR, element analysis, and nitrogen adsorption–desorption isotherms. The removal efficiency of p-nitrophenol from the aqueous solution by adsorption onto solid IHA surfaces was shown to be a function of pH, reaction temperature, and p-nitrophenol concentration. Adsorption equilibrium data satisfactorily fitted the Langmuir adsorption isotherm. Under a certain concentration range, the removal rate of p-nitrophenol at pH 3.5 could reach 24, 29, and 35 mg/g at a temperature of 25, 35, and 45±0.1°C. The results suggest that IHA could play a role as a potential efficient absorbent to remove organic contaminants, e.g., utilized to purify water contaminated by organic compounds.     

A study of turbulent characteristics of atmospheric boundary layer over monsoon trough region using Kytoon and Doppler sodar

As a part of the MONTBLEX-90 observational programme, Kytoon and Doppler sodar observations were taken at Kharagpur. These data are analysed to study the turbulent characteristics of the atmospheric boundary layer in terms of stability, temperature structure function (C _T ² ) and velocity structure function (C _v ² ).C _T ² follows aZ ^−4/3 law on most of the days, whereas the variation ofC _V ² is not systematic.C _V ² andC _T ² values are found to vary between 10⁻⁵−10⁻¹ m^4/3s⁻² and 10⁻⁵−10⁻²°C² m^−2/3 respectively.